1. Field Of The Invention
The invention is in the field of phenol chemistry.
2. Description Of The Background Art
The disclosed novel compound is derived from cardanol, a product obtained by treating cashew nut shell liquid (CNSL). CNSL consists primarily of anacardic acid which is decarboxylated when heated in the presence of acid, giving the meta-substituted phenol, cardanol, used in this invention. (See FIG. 1). Without further refining the resulting product contains a minor amount of a related compound, cardol. (See FIG. 2).
CNSL derivatives have found many industrial uses in, for example, epoxy curing agents, phenolic resins, surfactants, and emulsion breakers. These surfactant-emulsification compounds are oxalkylated to increase their molecular weight and modify their solubility or hydrophilic/lipophilic balance. For example a British patent GB 2,262,525 discloses ethoxylating cardanol with ethylene oxide to form a family of compounds of the formula C.sub.15 H.sub.31-2x C.sub.6 H.sub.4 O(C.sub.2 H.sub.4 O).sub.n H, where n is 3 or more, to produce the desired surface-active properties in which there is a balance between the hydrophilic and lipophilic ends of the molecule.
U.S. Pat. No. 2,448,767 disclosed a method of hydroxyethylation wherein ethylene carbonate or ethylene sulfite was reacted with phenols or other active hydrogencontaining compounds, such as thiophenols, amines, alcohols, thioalkohols, and carboxylic acids. The disclosed catalysts included an acid (concentrated sulfuric acid or an alkyl ether of sulfuric acid), a base (alkali carbonates), or the alkali salt of a phenol.
U.S. Pat. No. 2,967,892 disclosed that alkali metal hydroxides were effective catalysts in the hydroxyalkylation reactions of chloromethylethylene carbonate with phenols. U.S. Pat. No. 2,987,555 disclosed that alkali metal hydrides were effective catalysts in the hydroxyalkylation reactions of ethylene carbonate with phenols.
U.S. Pat. No. 4,310,706 disclosed the use of imidazole and its derivatives as catalysts for the reaction of phenols or thiophenols and cyclic organic carbonate compounds with high yields and good monohydroxyalkylation selectivity.
These prior art processes have not been used with cardanol before. Because of the unique molecular structure of cardanol (a long unsaturated side alkyl chain on the benzene ring), the principles disclosed in the prior art processes do not apply in the case of cardanol. For example, these teachings would imply that the use of basic catalysts could produce a significant amount undesirable by-product of secondary reactions between the hydroxyalkylphenyl ether and the carbonate reactant.